title: Purification and properties of the cellulases from the thermophilic fungus Thermoascus aurantiacus.
abstract: Three cellulases and a beta-glucosidase were purified from the culture filtrate of the thermophilic fungus Thermoascus aurantiacus. The isolated enzymes were all homogeneous on polyacrylamide-disc-gel electrophoresis. Data from chromatography on Bio-Gel P-60 and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated mol.wts. of 87000 (beta-glucosidase), 78000 (cellulase I), 49000 (cellulase II) and 34000 (cellulase III); the carbohydrate contents of the enzymes were 33.0, 5.5, 2.6 and 1.8% (w/w) respectively. Although the three purified cellulases were active towards filter paper, only cellulases I and III were active towards CM(carboxymethyl)-cellulose. Cellulase I was also active towards yeast glucan. The Km and catalytic-centre-activity values for the enzymes were as follows; 0.52 mumol/ml and 6.5 X 10(4) for beta-glucosidase on p-nitrophenyl beta-D-glucoside, 3.9 mg/ml and 6.3 for cellulase I on CM-cellulose, 1.2 mg/ml and 1.1 for cellulase I on yeast glucan, 35.5 mg/ml and 0.34 for cellulase II on filter paper, and 1.9 mg/ml and 33 for cellulase III on CM-cellulose.
mesh_terms: D001203:Ascomycota / Q000201:enzymology*; D002241:Carbohydrates / Q000032:analysis; D002480:Cellulase / Q000302:isolation & purification*; D004355:Drug Stability; D004591:Electrophoresis, Polyacrylamide Gel; D005959:Glucosidases / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000302:isolation & purification*; D007700:Kinetics; D008970:Molecular Weight; D013696:Temperature; D001617:beta-Glucosidase / Q000302:isolation & purification*
chemical_list: D002241:Carbohydrates; D007527:Isoenzymes; D005959:Glucosidases; D001617:beta-Glucosidase; D002480:Cellulase